Biodemography of Exceptional Longevity in the United States Abstract This project proposes to investigate why some people manage to survive to extreme old age (100+ years) and what are the biological and social correlates of exceptional longevity. These are important issues not only for demographic forecasts of human mortality and population aging, and the policy implications on health-care and pension expenditures, but also for improving our understanding of the fundamental mechanisms of human aging and longevity. The project will take advantage of the ongoing revolution in information technology for human longevity studies to examine the determinants of exceptional survival both on individual and population levels, using a rich variety of the U.S. data sources available through the Internet, including Social Security Administration datasets, Census data, family reconstitutions and validated genealogies, and military draft records. Recent findings from the P.I.'s pilot study of U.S. centenarians, funded by the Chicago Center on Aging (under NIA grant #P30 AG012857) and the Society of Actuaries, suggest that differences in chances of exceptional survival as large as two or three times can be linked to early-life circumstances, such as mother's age at person's birth, person's birth order, birth place within the United States, and family socioeconomic background. The plasticity of exceptional longevity in response to early-life living conditions indicates that environmental and behavioral factors cannot be overlooked in longevity studies. Even the search for human longevity genes could be facilitated when powerful confounding effects of childhood environment are taken into account. This project therefore proposes to explore the effects of early-life living conditions, adult physical characteristics, marriage, and reproductive history on exceptional longevity, and will test a number of related biomedical and social hypotheses. The project is designed as an interdisciplinary study of exceptional human longevity. To contribute to the research infrastructure for subsequent longevity studies world-wide, the P.I. will also develop a database with integrated, matched information on longevity predictor variables, and make it available to the research community on the Internet. The project will allow establishing scientific collaboration of the Center on Aging, NORC/University of Chicago with researchers at the University of Pennsylvania, the University of Utah, and the University of Wisconsin-Madison to study the biodemography of exceptional longevity in an interdisciplinary context.